Van Lent P L, Van De Loo F A, Holthuysen A E, Van Den Bersselaar L A, Vermeer H, Van Den Berg W B
Department of Rheumatology, University Hospital, St. Radboud, Nijmegen, Netherlands.
J Rheumatol. 1995 Dec;22(12):2250-8.
To determine the regulating role of interleukin-1 alpha and beta (IL-1 alpha, beta) and tumor necrosis factor alpha (TNF-alpha) on inhibition of proteoglycan synthesis and proteoglycan degradation in early immune complex arthritis (ICA) in the mouse.
In the early phases of arthritis, IL-1 and TNF were measured using cytokine specific bioassays, the NOB.1 EL-4 and L929 assay, respectively. The impact of IL-1 in proteoglycan synthesis was studied by neutralizing the formed IL-1 during early arthritis either by giving anti-IL-1 specific antibodies intravenously or IL-1 receptor antagonist (IL-1ra) intraperitoneally by osmotic pumps. TNF-alpha was neutralized by giving monoclonal antibodies directed against murine TNF-alpha. Synthesis of proteoglycans was measured ex vivo by uptake of 35S-sulfate by patellae derived from inflamed and control, noninflamed knee joints. In vivo formation of 35S-sulfate labeled proteoglycans was studied by autoradiography. Degradation of proteoglycans was measured by labeling patellae in vivo with 35S-sulfate before arthritis induction.
High levels of IL-1 are formed during the first phase of immune complex arthritis (ICA). Neutralization of either IL-1 alpha or beta with specific polyclonal antibodies resulted only in partial blocking, whereas a combination fully blocked inhibition of proteoglycan synthesis. Full blocking was also found after systemic treatment with high amounts of IL-1 receptor antagonist (1.2 mg/day during 3 days). Influx of cells was also significantly reduced both in the anti-IL-1 as well as in the IL-1ra treated groups. Whether infiltrating cells are involved in inhibition of proteoglycan synthesis was further investigated in neutropenic mice. Significantly higher levels of IL-1 were found in arthritic joints of neutropenic compared with control mice. Suppression of proteoglycan synthesis was similar in arthritic knee joints of normal and neutropenic mice. However, only minor proteoglycan degradation was found in the latter. TNF-alpha was undetectable in the bioassay in early ICA and neutralization of TNF-alpha did not change either swelling, cell influx, proteoglycan synthesis or proteoglycan degradation.
Local production of IL-1 in ICA in knee joints seems directly responsible for inhibition of proteoglycan synthesis. A direct role of IL-1 in proteoglycan loss is unlikely, but indirectly IL-1 may be involved in proteoglycan breakdown by attracting inflammatory leukocytes and activating synovial cells. TNF-alpha seemed to have no effect on either cell influx, proteoglycan synthesis or proteoglycan degradation in this model.
确定白细胞介素-1α和β（IL-1α、β）以及肿瘤坏死因子-α（TNF-α）对小鼠早期免疫复合物关节炎（ICA）中蛋白聚糖合成抑制和蛋白聚糖降解的调节作用。
在关节炎早期阶段，分别使用细胞因子特异性生物测定法（NOB.1 EL-4和L929测定法）测量IL-1和TNF。通过在早期关节炎期间静脉注射抗IL-1特异性抗体或通过渗透泵腹腔注射IL-1受体拮抗剂（IL-1ra）来中和形成的IL-1，研究IL-1对蛋白聚糖合成的影响。通过给予针对小鼠TNF-α的单克隆抗体来中和TNF-α。通过摄取来自发炎和对照非发炎膝关节的髌骨中的35S-硫酸盐来离体测量蛋白聚糖的合成。通过放射自显影研究35S-硫酸盐标记的蛋白聚糖在体内的形成。通过在关节炎诱导前用35S-硫酸盐在体内标记髌骨来测量蛋白聚糖的降解。
在免疫复合物关节炎（ICA）的第一阶段形成高水平的IL-1。用特异性多克隆抗体中和IL-1α或β仅导致部分阻断，而联合使用则完全阻断蛋白聚糖合成的抑制。在用大量IL-1受体拮抗剂进行全身治疗后（3天内每天1.2毫克）也发现了完全阻断。在抗IL-1以及IL-1ra治疗组中，细胞流入也显著减少。在中性粒细胞减少的小鼠中进一步研究了浸润细胞是否参与蛋白聚糖合成的抑制。与对照小鼠相比，中性粒细胞减少的关节炎关节中发现IL-1水平显著更高。正常和中性粒细胞减少的小鼠的关节炎膝关节中蛋白聚糖合成的抑制相似。然而，在后者中仅发现少量蛋白聚糖降解。在早期ICA的生物测定中未检测到TNF-α，并且TNF-α的中和并未改变肿胀、细胞流入、蛋白聚糖合成或蛋白聚糖降解。
膝关节ICA中IL-1的局部产生似乎直接导致蛋白聚糖合成的抑制。IL-1在蛋白聚糖丢失中不太可能起直接作用，但IL-1可能通过吸引炎性白细胞和激活滑膜细胞间接参与蛋白聚糖的分解。在该模型中，TNF-α似乎对细胞流入、蛋白聚糖合成或蛋白聚糖降解均无影响。
